Sensor elements are generally known. For example, an acceleration sensor, which has a seismic mass which is movably suspended on a substrate and is deflectable in a direction parallel to the substrate via external acceleration forces, and has evaluation means for detecting an acceleration-induced deflection of the seismic mass parallel to the substrate, is described in German Patent No. DE 197 19 779. Furthermore, an acceleration sensor, which includes a seismic mass designed in the form of an asymmetrical rocker structure for detecting acceleration effects perpendicular to the substrate, is described in German Patent No. DE 10 2007 048 882. Detection of acceleration forces which act upon the seismic mass both perpendicular and parallel to the substrate with the aid of only a single acceleration sensor is not provided for. Furthermore, an excitation element is not provided between the seismic mass and the substrate.